To enhance or increase the production of oil and gas hydrocarbons from wells bored into subterranean formations, it has been common practice to pump a viscous fluid at high pressure down into the wellbore to fracture the formation and force the fracturing fluid into those fractures. The fracturing fluid may also be used to carry sand or other types of particles, called proppants, to hold the fractures open when the pressure is relieved. The fractures held open by the proppant provide additional paths for the oil or gas to reach the wellbore, which increases production from the well.
Because of the high volume of fracturing fluids used, it is desirable to thicken the fracturing fluids with thickeners. Efficient thickeners such as guar gum, and derivatized guar gum, are commonly used. The viscosity of solutions of guar gum and similar thickeners can be greatly enhanced by crosslinking them with metal containing materials. Thus, metal crosslinked guar gum and derivatized guar gum, are useful as fracturing fluids.
Metals, such as boron and metal (aluminum, zirconium, titanium, antimony) complexes are commonly used in the oilfield industry as crosslinkers for these water soluble polymers.
Even with or without such crosslinking agents, at higher temperatures, the viscosity of the polymer thickened fluids may breakdown so that the fluid viscosity is reduced and the fluid is less effective.
Accordingly, improvements are needed in those polymer fluids used and methods of using such fluids in high temperature applications, such as high temperature fracturing operations.